


Growth

by preusterreich



Category: Free!
Genre: Fairy!Rei, Incubus!Rin, M/M
Language: English
Status: Completed
Published: 2016-08-14
Updated: 2016-08-14
Packaged: 2018-08-08 15:12:26
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,016
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7762711
Author URL: https://archiveofourown.org/users/preusterreich/pseuds/preusterreich
Summary: <blockquote class="userstuff">
              <p>When an army attacks Rin and Rei, Rin must transform into his full-demon form to save them both.</p>
            </blockquote>





	Growth

**Author's Note:**

  * For [TiBun](https://archiveofourown.org/users/TiBun/gifts).



> This is a quick drabble based on an RP I'm doing with TiBun! I'm Rin, they're Rei.
> 
> We also may post the full rp one day because honestly it's pretty entertaining so far and I think you guys would enjoy it! I'm really excited to see where it goes!~

"How's your wing?" Rin asked, glancing at the small tattered area of Rei's left wing. He had gotten the delicate membrane stuck on a bit of thorny bush, and it had been damaged and torn. Rei assured him that it would heal, but it was going to take a few days at least. 

Rei fluttered his wings quickly, but he could not lift his body off the ground. "Better, but still out of commission."

Rin grunted in reply, then smiled. "Do you want to see something beautiful, Rei?" he asked from his seat near the brook. 

Rei glanced over at his demon companion, his eyes wide and lips pursed in curiosity. "What is it?" he asked lightly.

Rin smiled, tilting his head toward some bushes. "A surprise," he drawled.

Giggling at Rin's playful words, Rei nodded and stood. Rin followed him up, standing at his full height - just a few inches taller than Rei while on his hooves. He trotted over to the thick brush and gestured for Rei to join him.

When Rei reached his side, Rin parted the bushes and allowed Rei to look out over the open meadow. Rei's breath caught in his throat at the sight. He moved out over the grass, his thin wings fluttering as he walked. The setting sun cast a heavenly glow on the softly-swaying grass, and Rei could hear the river past the rustling leaves. The sound was soothing and made him think of home.

"My god, Rin, this place is gorgeous." Rei stared at the landscape, venturing further out as dust motes and pollen floated through the breeze as though caught in the water of the stream. Rei turned back to Rin, standing face to face in the middle of the plain. "But why did you want to show me this?" 

Rin rubbed at the back of his neck, a soft blush spreading across his cheeks. "I wondered if... maybe you wanted to, well... live here. You don't like it under the mountain, right? We could build a house here..."

Rei felt goosebumps prickle his skin. "Rin..." He caressed Rin's cheek softly as he tried to quell his hammering heart. "I would love that."

A silent arrow cut through the air next to them, barely missing the flesh of Rin's wing. Rin quickly turned around 180°, snarling in the direction that the arrow had come from, but he saw nothing. "Get behind me," he growled at Rei and tucked him close behind himself, scanning the trees for any movement. His eyes burned red and his teeth elongated in a gesture of intimidation.

Rei's heart was still beating wildly, but he saw a rustle of leaves off to the right. 

"Rin, there!" He pointed to the bush as an armored figure emerged. Rin's head snapped to the right as the man approached, his army following him out of the brush, seemingly endless in number.

Heat radiated off Rin's body in waves as his eyes seared bright red. Rei gripped tightly to his shoulders.

"Rin, there are so many of them," Rei whispered, shivering in terror as the horde closed in. He heard murmurs that sounded suspiciously like 'kill the demon.'

The captain suddenly stopped about fifteen feet away from the pair, holding up his hand to halt the rest of the army's advance as well. 

Then he spoke.

"The day's tracking has paid off, men. We have cornered the demon and his puppet. We shall kill them both!"

Rei jumped in front of Rin to protect him. "No! Please!"

"Ignore the fairy! He is under the demon's spell! Arm yourselves, and beware the demon! He is strong!" The soldiers drew their swords and stood at attention, awaiting the orders from their captain.

"Rei," Rin pulled Rei behind him again. "I know I promised you that I would never show you my full demon form before you were ready," He looked into Rei's eyes. "but now's a good time to be ready. I can't fight them all like this."

Rei nodded tentatively. "I'm ready."

"When I'm fully transformed, get on my back," Rin instructed, tucking Rei even tighter behind him as his height began to increase. His hands bubbled into meaty claws and his chest grew as muscle swelled on his form. Rei was awestruck as he watched Rin grow and change and twist. Bones seem to break and reform instantly and his hooves grew giant and black, thick muscle filling his legs to support his massive upper body. 

The army was struck dumb too, still as they watched the demon transform, and if Rei had been able to tear his gaze from Rin, he would have noticed a few of the men in the back ranks flee in terror. 

Rei saw Rin's face elongate until it was almost equine or wolfish in form and his teeth grew long and sharp like needles, sticking out of his snout at odd angles. His horns thickened as his skull grew wider and the expanse of his back bulged grotesquely. He watched Rin's skin turn maroon red as his hair and wings fell away from his body. Rin reared up onto his back legs and roared into the air, shaking Rei to his very core. 

Rin was around twelve feet tall in his demon form, but his back legs were almost too weak to support his supremely-muscular upper body, so he walked mostly on all fours.

"Men, don't cower! We must slay the demon and his puppet," the captain of the army called over the crowd.

Rin turned quickly back to face Rei, willing him to climb onto his back, but Rei stood frozen under Rin's pure red eyes burning bright like an inferno.

Rin closed his eyes and shook his head, calming the fire in his gaze. He opened his eyes once more and Rei saw his normal eyes, caring eyes that he had seen tentative and unsure of themselves, eyes that had showed him such tender affection, and he knew that this monster in front of him was nothing for him to fear. He leapt toward Rin, winding his arms around the demon's neck in a tight hold as the army began the charge.

Rin roared again and swiped at the soldiers, easily tearing a few of them away from the crowd, but more swarmed in to take their place. Rei closed his eyes tightly and held on, not wanting to watch the carnage and also trusting Rin to protect him. He felt that Rin's skin was quite a bit tougher in this form than usual, which was probably why the sword blows of the men seemed to bounce off his arms and legs. Rei heard the clattering of swords and armor as Rin knocked the men away from them.

Then Rei had an idea, his eyes shooting open.

"Rin!" he called into Rin's ear over the deafening noise of the battle. "Kill the captain!! It will lower the morale of the rest!"

Rin nodded once and cleared a path through the horde, thundering toward the leader that had approached them first. A few more soldiers had retreated at Rin's easy massacre of the front line factions. He grabbed the captain (easily identifiable through the chaos by his extravagant helmet) around the waist and lifted him up off the ground, stopping the rest of the army in their tracks. 

"Put me down, monster!" The captain swiped at Rin with his sword, the sharp point catching him on the side of the face. Rin growled as blood slid from his wound, dripping slowly from his chin.

"Come on, men! Kill the beast!" he yelled, but the army was silent and still as Rin held the leader in his grip, their confidence waning.

"But our blows do nothing! We should retreat!" called one.

"I agree! The monster is invincible!"

"Let's get out of here!"

And with that, the army scattered, running scared from the demon still holding their captain high in the air.

Rei looked over at the man and smiled. "Your men are gone," He patted Rin on the shoulder. "and he didn't even have to kill you. What a laughable army." Rin growled in agreement, showing off his teeth in some sort of twisted grin. "I'll get him to let you go if you promise to never return to this place."

The man took another look at the fire in Rin's brimstone eyes and his giant, twisted teeth and sighed in defeat. "Fine. I would like to live to see my family again."

Rei laid a hand on Rin's cheek, trying to avoid the dribbling blood. "And we would as well," he said to the man, earning a nod of agreement from Rin. 

Rin set him down on the earth, allowing him his life and freedom.

"If you return, we may not be so lenient next time," Rei called after the man as he retreated beyond the trees to join his army. 

"Rin, let me down." 

Rin ducked toward the ground and allowed Rei to jump down from his back. He then sat back on his haunches and bowed his head.

"That was amazing, Rin." Rei stood directly in front of Rin, smiling and stroking his snout gently. "Thank you for protecting me."

Then Rin's eyes were his own eyes again, not the intense red of his demon form. There was care and love and concern behind them instead of intimidation and anger.

He kissed Rin's snout, carefully avoiding his sharp teeth. When he pulled back, Rin began to shift once more, his body becoming more compact as his muscles shrunk and his skin returned to its usual peachy tone. His face became more human like and Rin finally looked like himself again as his crimson hair regrew over his scalp. After a few more seconds of transformation, Rin was on his knees in front of Rei, and other than missing his wings, was completely himself once more.

"I'm so sorry, Rei. I should have noticed that they were following us." Rin said shakily, reaching up to circle his arms around Rei's waist. "An army that large should have been so easy for me to smell on the breeze. God, I'm so useless," he whimpered.

Rei slid down to his knees as well, wiping a bit of dried blood from Rin's cheek before wrapping his arms around his neck. He laid a soft, lingering kiss upon Rin's lips, then pulled back after a moment.

"You're not useless; you just saved both of our lives. You protected us from the threat when it made itself known, and that's all I could ask for." Rei assured him. "You did good, Rin."

"I'm glad you're not hurt." A flush crept over his face. "Rei, I don't really know how to say this, but," He lowered his gaze to the ground. "I really love you." 

Rei smiled widely and felt tears well in his eyes. "I know you do, Rin, and I love you too." 

Surprised by Rei's reaction, Rin snapped his gaze to Rei, but he could say nothing.

"Rin, I want to be your mate."

Rin was speechless. It took everything he had to construct a coherent sentence. "Really? You want to be with me? Forever?"

Rei caressed Rin's cheek and laughed lightly. "Of course. We may not have started off in a good place, but you have shown me how much you've grown and how gentle and kind you can be. I love you and I want to live here with you." He gave Rin a quick kiss. "There's nothing that I want more than that." 

Rin breathed out a laugh. "I can't believe how lucky I am."

"Luck has nothing to do with it; you've worked hard, Rin," Rei smiled. 

Suddenly, Rin's expression grew thoughtful. 

"What's with that look?" Rei asked.

"You know, we're going to need some powerful magic to keep armies like that one away all the time, and we're gonna have to clean up all these bodies," Rin stated, looking out over the fallen soldiers.

Rei chuckled under his breath. "I'm sure we can make do."


End file.
